Butyrate supplementation to pregnant mice elicits cytoprotection against colonic injury in the offspring

The Microbial Metabolite δ-Valerobetaine Strengthens the Gut Epithelial Barrier

Metabolic processes within gut microbes generate bioactive metabolites that impact intestinal epithelial barrier function. Using gnotobiotic mice and mass spectrometry-based metabolomics, novel metabolites in host tissues that are of microbial origin were identified. Of those detected, it was shown that the gut microbe-generated metabolite δ-valerobetaine (δ-VB) is a potent inhibitor of l-carnitine biosynthesis and a modulator of fatty acid oxidation by mitochondria in liver cells. In the current study, the bioactivity of δ-VB toward gut epithelial barrier function was assessed. Germ-free mice are devoid of δ-VB, and administration of δ-VB to germ-free mice also induces the enrichment of transcript sets associated with gut mitochondrial respiration and fatty acid oxidation in colonic tissue. Furthermore, δ-VB induces the differential expression of genes that function in barrier function in germ-free and conventionally raised mice. Functionally, δ-VB decreased gut barrier permeability and augmented wound healing in cultured gut epithelial cells and elicited cytoprotective and prorestitutive effects in a mouse model of colonic injury. We conclude that the microbial-derived metabolite δ-VB is a modulator of gut epithelium function, and thus is a molecular target to potentially manage microbiome-host dysbiosis in intestinal health and disease.

Lactational high weight loss impairs follicular development by causing mitochondrial dysfunction of ovarian cells in sows and mitigated by butyrate supplement

INTRODUCTION

In modern sows, lactational high weight loss (HWL), caused by the large litter size and inadequate feed intake, has a negative effect on follicular development after weaning, resulting in poor reproductive performance in the subsequent parity. However, the underlying mechanism remains unclear.

OBJECTIVES

This research aimed to explore the mechanism that sows HWL during lactation damages follicular development and attempt to improve the reproductive function by treating with butyrate.

METHOD

Four multiparous sister sows were chosen to build a HWL model for lactating sows through feed restriction during the final week of a 21-day lactation. Spatially transcriptomics (ST) and tissue immunofluorescent staining were then utilized for the antral follicles in the ovarian surface to search for differentially expressed genes and proteins among different cell types. Subsequently, the mouse assay, including immunofluorescent staining, transmission electron microscopy, hormone detection and western blot, were conducted to verify the findings in sows and investigate the effect of butyrate on the follicular development in HWL mice.

RESULTS

Based on the transcriptomic analysis, differentially expressed genes in granulosa cells, theca cells, and ovarian stromal cells were examined. The findings revealed that HWL disturbs the mitochondrial electron transport chain and steroidogenesis in all three cell types by downregulating the expression of NDUFB3, SDHB, CYCS, COX8A and CYP19A1, as well as upregulating the expression of STAR, CYP11A1 and CYP17A1. Furthermore, results from mouse assays demonstrated that HWL causes apoptosis and alters sex hormone secretion by impairing mitochondrial function and disordering the expression of steroidogenesis key enzymes in ovarian cells, while these effects were partially mitigated by butyrate treatment.

CONCLUSION

The mitochondrial dysfunction and abnormal steroidogenesis induced by HWL during lactation in ovarian cells harm the follicular development of weaning sows, which could be alleviated by butyrate treatment.

Short-chain fatty acids in fetal development and metabolism

Short-chain fatty acids (SCFAs), primarily derived from gut microbiota, play a role in regulating fetal development; however, the mechanism remains unclear. Fetal SCFAs levels depends on maternal SCFAs transported via the placenta. Metabolic stress, particularly from diabetes and obesity, can disrupt maternal SCFAs levels, impairing fetal metabolic reprogramming. Dysregulated SCFAs may negatively impact the development of the fetal cardiovascular, nervous, and immune systems, potentially contributing to adverse outcomes in adulthood. This review focuses on recent advances regarding the role of maternal SCFAs in shaping the metabolic profile of offspring, especially in the context of various maternal metabolic disorders. Given that SCFAs may influence fetal development through the placenta-embryo axis, targeted SCFAs supplementation could be a promising strategy against developmental diseases associated with intrauterine risk factors.

The impact of butyrate on group B Streptococcus-induced intestinal barrier disruption

Group B Streptococcus (Streptococcus agalactiae; GBS) is a leading cause of neonatal sepsis worldwide. As a pathobiont of the intestinal tract, it is capable of translocating across barriers leading to invasive disease. Neonatal susceptibility to invasive disease stems from immature intestinal barriers. GBS intestinal colonization induces major transcriptomic changes in the intestinal epithelium related to barrier function. Butyrate, a microbial metabolite produced by fermentation of dietary fiber, bolsters intestinal barrier function against enteric pathogens, and these effects can be transferred in utero via the placenta to the developing fetus. Our aim was to determine if butyrate mitigates GBS disruption of intestinal barriers. We used human intestinal epithelial cell (IEC) lines to evaluate the impact of butyrate on GBS-induced cell death and GBS adhesion and invasion. IECs and human fetal tissue-derived enteroids were used to evaluate monolayer permeability. We evaluated the impact of maternal butyrate treatment (mButyrate) using our established mouse model of neonatal GBS intestinal colonization and late-onset sepsis. We found that butyrate reduces GBS-induced cell death, GBS invasion, monolayer permeability, and translocation in vitro. In mice, mButyrate decreases GBS intestinal burden in offspring. Our results demonstrate the importance of bacterial metabolites, such as butyrate, in their potential to bolster epithelial barrier function and mitigate neonatal sepsis risk.IMPORTANCEGroup B Streptococcus (GBS) is a leading cause of neonatal morbidity and mortality. It is a commensal of the intestines that can translocate across barriers leading to sepsis in vulnerable newborns. With the rise in antibiotic-resistant strains and no licensed vaccine, there is an urgent need for preventative strategies. Butyrate, a short-chain fatty acid metabolized in the gut, enhances barrier function against pathogens. Importantly, butyrate is transferred in utero, conferring these benefits to infants. Here, we demonstrate that butyrate reduces GBS colonization and epithelial invasion. These effects were not microbiome-driven, suggesting butyrate directly impacts epithelial barrier function. Our results highlight the potential impact of maternal dietary metabolites, like butyrate, as a strategy to mitigate neonatal sepsis risk.

Alcohol consumption during pregnancy differentially affects the fecal microbiota of dams and offspring

Microbiota imbalances are linked to inflammation and disease, as well as neurodevelopmental conditions where they may contribute to behavioral, physiological, and central nervous system dysfunction. By contrast, the role of the microbiota in Fetal Alcohol Spectrum Disorder (FASD), the group of neurodevelopmental conditions that can occur following prenatal alcohol exposure (PAE), has not received similar attention. Here we utilized a rodent model of alcohol consumption during pregnancy to characterize the impact of alcohol on the microbiota of dam-offspring dyads. Overall, bacterial diversity decreased in alcohol-consuming dams and community composition differed from that of controls in alcohol-consuming dams and their offspring. Bacterial taxa and predicted biochemical pathway composition were also altered with alcohol consumption/exposure; however, there was minimal overlap between the changes in dams and offspring. These findings illuminate the potential importance of the microbiota in the pathophysiology of FASD and support investigation into novel microbiota-based interventions.

A high fiber diet or supplementation with Lactococcus lactis subspecies cremoris to pregnant mice confers protection against intestinal injury in adult offspring

The diet during pregnancy, or antenatal diet, influences the offspring's intestinal health. We previously showed that antenatal butyrate supplementation reduces injury in adult murine offspring with dextran sulfate sodium (DSS)-induced colitis. Potential modulators of butyrate levels in the intestine include a high fiber diet or dietary supplementation with probiotics. To test this, we supplemented the diet of pregnant mice with high fiber, or with the probiotic bacteria Lactococcus lactis subspecies cremoris or Lactobacillus rhamnosus GG. We then induced chronic colitis with DSS in their adult offspring. We demonstrate that a high fiber antenatal diet, or supplementation with Lactococcus lactis subspecies cremoris during pregnancy diminished the injury from DSS-induced colitis in offspring. These data are evidence that antenatal dietary interventions impact offspring gut health and define the antenatal diet as a therapeutic modality to enhance offspring intestinal health.

Microbial transmission, colonisation and succession: from pregnancy to infancy

The microbiome has been proven to be associated with many diseases and has been used as a biomarker and target in disease prevention and intervention. Currently, the vital role of the microbiome in pregnant women and newborns is increasingly emphasised. In this review, we discuss the interplay of the microbiome and the corresponding immune mechanism between mothers and their offspring during the perinatal period. We aim to present a comprehensive picture of microbial transmission and potential immune imprinting before and after delivery. In addition, we discuss the possibility of in utero microbial colonisation during pregnancy, which has been highly debated in recent studies, and highlight the importance of the microbiome in infant development during the first 3 years of life. This holistic view of the role of the microbial interplay between mothers and infants will refine our current understanding of pregnancy complications as well as diseases in early life and will greatly facilitate the microbiome-based prenatal diagnosis and treatment of mother-infant-related diseases.